1. Field of the Invention
The present invention relates to an illuminating apparatus and a photo-excited process apparatus using the same. More particularly, the present invention relates to an illuminating apparatus of a photo-excited process apparatus which is used to manufacture semiconductor elements and electronic circuits and which requires that light having high illuminance be uniformly applied with a small amount of chromatic aberration to a base having a large area.
2. Description of the Related Art
A photo-excited process apparatus is expected to be put into practical use as a manufacturing process semiconductor elements apparatus for semiconductor elements, electronic circuits and, in particular, very-large-scale integrated circuits (VLSIs) because theoretically it can process at low temperatures with little damage. At the present time, a photo-excited process apparatus has come to be applied to a cleaning apparatus or an annealing apparatus, and further applications thereof in a film forming apparatus, an etching apparatus and the like have been considered. In recent years, as VLSI manufacturing processes process bases having larger areas, the illuminating apparatus of the photo-excited process apparatus is also required to process bases having larger areas while at the same time maintaining high illuminance and uniformity.
FIG. 5 is a cross-sectional view which illustrates the construction of a conventional illuminating apparatus used in a photo-excited process apparatus. Shown in FIG. 5 is a multi-lamp array type apparatus which comprises a great number of arranged bar-shaped lamps 501 and a plurality of back mirrors 502, one of each such mirrors being provided on the back of each of the bar-shaped lamps 501. The light generated from each of the lamps 501 is directly guided to, or reflected by, a corresponding back mirror 502 and guided to a process chamber (not shown) disposed below the multi-lamp array.
FIG. 6 is a cross-sectional view which illustrates the construction of another conventional illuminating apparatus used in a photo-excited process apparatus, and also illustrates a fly-eye lens. Light which is generated from a point lamp 601 and made into a substantially parallel light flux by a back mirror 602 provided on the back of the point lamp 601 passes through a fly-eye lens 603 in which very small lenses are arranged two-dimensionally, and then through a collimator lens 604 and guided to a process chamber (not shown) disposed below the fly-eye lens 603. The light flux is enlarged and made uniform as a result of passing through the fly-eye lens 603, and is made a parallel light flux as a result of passing through the collimator lens 604.
However, the prior art has the problems described below. Of the above-described conventional apparatuses, the multi-lamp array type has a high cost because it requires a large number of lamps. The illuminance is sharply decreased when a base to be processed is located away from a lamp to make the illuminance uniform. In the fly-eye lens, since all light generated from the point lamp passes through the fly-eye lens, if the light intensity of the point lamp is increased, the fly-eye lens overheats, causing a cloudiness and transmittance is decreased. Also, since chromatic aberration occurs when a wideband lamp is used, the degree of the uniformity is not constant.